1. Field of the Invention
The present invention generally relates to devices used for straightening teeth and, more particularly, is concerned with an adjustable orthodontic bracket assembly with continuous adjustment in any one of six planes of motion.
2. Description of the Prior Art
Orthodontic clinicians practice the art and science of moving teeth into their most optimum position for the use and comfort of patients. Various types of brackets have been employed by clinicians to achieve this task. Generally, anchors and one or more arch wires (so-called because the teeth are setting in upper and lower jaws in the form of an arch) connected to the anchors are secured to the front faces of the teeth. Up to three arch wires may be utilized during the time period in which a patient wears the bracket. The portion of each arch wire at the location of each tooth to be straightened is bent such that forces reactive with the arch wire and a respective anchor attached to the tooth cause the tooth to gradually straighten as desired.
In the past, the clinician had to periodically remove the arch wire and make new bends in it or replace the arch wire with a new one and introduce the new bends in the replacement arch wire to continue the process of straightening the teeth. By removing and placing various bends in the arch wires and using a number of different auxiliaries, the clinician was able to move teeth in six planes of motion, including vertical translational (or up and down) motion, lateral translational motion (or bodily movement of a tooth toward or away from the tongue and palate), mesio/distal translational motion (or bodily movement of a tooth away from or towards the dental midline along the dental arch, the midline being the arch formed by the alignment of the upper and lower teeth), tip rotational motion about an axis extending perpendicular to front surface of tooth (or movement of the root or crown of the tooth toward and away from the midline in the plane tangent to the dental arch), torque rotational motion about an axis extending side to side through tooth (or movement of the root or crown of the tooth toward or away from the tongue or palate) and circular rotational motion about a tooth's longitudinal axis (extending vertically through tooth) in a clockwise or counterclockwise direction. The bending of the arch wire into a configuration to achieve a desired movement of the teeth, however, can be an imprecise way of straightening teeth as it has a high degree of dependency on trial and error which is influenced by the level of skill of the individual clinician.
A variety of orthodontic bracket assemblies have been developed over the years toward overcoming the above-mentioned problems. Representative examples of these orthodontic bracket assemblies are disclosed in U.S. Pat. No. 3,256,602 to Broussard et al., U.S. Pat. No. 3,721,005 to Cohen, U.S. Pat. No. 4,243,387 to Prins, U.S. Pat. No. 4,353,692 to Karrakussoglu, U.S. Pat. No. 4,487,581 to Adler, U.S. Pat. No. 4,496,317 to Hulsey, U.S. Pat. No. 4,597,739 to Rosenberg, U.S. Pat. No. 4,669,980 to Degnan, U.S. Pat. No. 4,676,746 to Klapper, and U.S. Re. Pat. No. 34,044 to Broussard. Problems exist, however, with these and other prior art assemblies, as well. Some prior art assemblies are complex in their design and/or use. Some prior art assemblies require removal of the arch wire to affect changes in orientation of teeth during treatment. None of the prior art assemblies incorporate more than two motion changes in a way in which movements are continuous and independent. In some prior art assemblies it is impossible to adjust movement of the tooth in some of the six planes without causing undesired movements in other planes. Some prior art assemblies allow for movement of the arch wire in up to five of the six planes of motion, but these assemblies also require replacement of parts or removal of the arch wire. Some prior art assemblies are also made of an array of relatively small interchangeable elements, and in many cases several of the six planes of motion are accomplished only with an interchangeable part such that the practical number of different parts needed to accomplish all six motions is quite large.
Consequently, a need still exists for an assembly which provides a solution to the aforementioned problems in the prior art without introducing any new problems in place thereof.